Research On The Variable Structure Stability Control Of The Linear Inverted Pendulum

The linear inverted pendulum is a classical equipment of university’s control laboratory in our country, research the stability control performance which such as multivariable, highly nonlinear, strong coupling and natural unstable systems, not only has the important theoretical significance, but also has a very practical guidance value to the engineering practice. The sliding mode variable structure control has excellent robustness and complete adaptability to the uncertainties and external disturbance, On the basis of the current research of the developed sliding mode variable structure control theory at home and abroad, linking theory with practice, sliding mode variable structure control theory is presented to the single and double linear inverted pendulum, stability control and real-time control research about the car and the pendulum have done in this paper.The sliding mode variable structure control based on sign function is presented to deal with the single inverted pendulum system, the violent chatting problem have appeared in the simulation results. Introducing saturation function to improve controller, the results show that it can effectively reduce the system chattering and improve the control quality of system based on reaching law of by saturation function, but the robustness isn’t strong. On the simulation platform of linear inverted pendulum system, it successfully realized the variable structure real-time control of the single inverted pendulum based on the C-MEX S-Function programs of two control scheme.The double linear inverted pendulum system is balanced by the sliding mode variable structure control based on exponential velocity reaching law, the sliding mode variable structure control based on reaching law of by saturation function and continuous function, and the sliding mode variable structure control based on fuzzy reaching law, results show that a single variable structure controller although able to accomplish the stability control of the linear pendulum, but the system has strong chattering. Even in this basis through the saturation function and continuous function to improve controller can reduce the chattering, but the quality of control system will fall. Combining the fuzzy logic control in variable structure control strategy, not only can through reduce chattering to improve the control quality of system, and still can keep the strong robustness of system.